The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
To produce dressings intended to support and stabilize limbs, plaster cast materials have been known for quite some time. In addition, alternative dressing material based on polymers has been in use for a while. Compared to the plaster casts, this material has the advantage that it has improved mechanical properties, in particular, washability and water resistance. In addition, the polymer material can be applied and cured more quickly and has a lower weight, thus guaranteeing increased comfort when wearing it, and improved mobility. Finally, compared to cast materials, the dressing materials based on polymers have the advantage that they allow x-rays to penetrate more easily and therefore enable x-ray check-ups without having to remove the dressing.
Both the plaster cast materials and the dressing materials based on polymers substantially comprise an organic or inorganic textile carrier material and the cast or polymer material applied thereon. With respect to the polymer materials, a differentiation is made between irreversibly curable materials and thermoplastic, reversibly deformable materials.
As irreversible polymer dressing materials, primarily water-curable systems are known, which comprise reactive polyurethane prepolymers as the curable polymer component, wherein the prepolymers harden upon contact with water. As long as the polymer is not hardened, the individual layers of the dressing material can be glued to each other, ultimately obtaining a dressing comprising a plurality of material layers.
In the case of thermoplastic reversibly deformable dressing materials, the self-adhesive property is achieved by heating the thermoplastic to the respective melting/softening temperature or above, so that the layers then enter a permanent bond when they are applied. As the material cools, it solidifies again, however for some time it still remains plastically deformable, even at temperatures below the melting point. Polymers of this type follow a hysteresis curve with respect to their melting and solidification properties. After the thermoplastic has completely solidified, a stable, multi-layer, bonded dressing system is obtained.
A corresponding dressing material is known, for example, from EP 1 029 521 A2, which discloses a thermoplastic dressing material that is rigid or semi-rigid at temperatures of 50° C. and below and self-adhesive in the pliable state, comprising a first textile web and a thermoplastic polymer applied to the first textile web, the thermoplastic having a melting point ranging from 55° C. to 90° C., and at least one second textile web that is applied to this material dressing. This allows for the adhesion of the layers on the finished dressing not to be negatively influenced, while the bandage is easy to unroll, even after squeezing out the remaining water after heating in a water bath. Thus the protective layer does not have to be removed, which clearly increases the ease of handling. Finally, in this way, a second, outwardly directed textile surface is achieved, which helps improve the surface character of the finished dressing. So as to create a colored dressing, color pigments may be added.
The disadvantage of the above-described design is that the color pigments can come in direct contact with the wearer as well as with the technician when applying the cast, and may result in undesirable skin reactions, such as skin irritation, sensitization or allergic reactions, due to the toxic components or decomposition products of the dyes. As a result, such colored cast bandages are associated with the problem that they cannot be worn permanently directly on the skin without additional skin-protecting materials, such as gauze, tube bandages, and crepe.